As stated previously (see Chapter 2.1), although Saccharomyces is virtually untraceable in the microbial flora of the grape, it very quickly dominates the fermentation so that at completion a nearly pure culture of this yeast is observed. Inoculation of the fermentation with Saccharomyces causes a faster domination of the fermentation by this organism. The reason for this domination can be found in the specific adaptation to high sugar, virtually anaerobic environments. Indeed, such environments appear to be the specific ecological niche in which this organism can flourish and dominate all other microorganisms. Yeast cells multiply during grape juice fermentation and their growth kinetics follow a typical microbial growth curve (Figure 2.2.1) which reflects the growth of cell number and decrease in sugar concentration (◦ Brix).